1. Field of the Invention
The present invention relates to a circuit breaker, and more particularly, to a frame for a circuit breaker which can reduce a manufacturing cost as well as facilitate its manufacture and reduce a manufacturing time.
2. Description of the Background Art
In general, a circuit breaker is connected to an electric circuit in which a current flows, and is a device which enables the current to flow in the electric circuit in a normal condition, and protects an electric circuit of an electrical power distribution system and a device, when a fault current (or an abnormal current) occurs in the electric circuit, by breaking the fault current.
There are various types of circuit breakers according to an amount of conducted current (voltage).
FIG. 1 is a cross-sectional view illustrating an exemplary circuit breaker, and FIG. 2 is a perspective view illustrating a body frame of the circuit breaker.
Referring to the drawings, the circuit breaker may include a body frame 10 having a plurality of spaces disposed in a row, a rear case 20 coupled to one side of the body frame 10, a plurality of fixed contactors 30 coupled to the rear case 20, movable contactors 40 rotatably coupled to the body frame 10 so as to be disposed in each space of the body frame 10, an operating mechanism 50 coupled to the body frame 10 and driving the movable contactors 40, and a cover 60 coupled to the body frame 10 and covering the operating mechanism 50.
As the rear case 20 is coupled to the body frame 10, spaces of the body frame 10 form rear spaces 11, and a front space 61 is formed between the body frame 10 and the cover 60.
An exhaust unit 70 for exhausting an arc generated when the movable contactor 40 contacts or is spaced from the fixed contactor 30 is coupled at each upper portion of the rear spaces 11.
Outlet-side fixed contacts 32 of the fixed contactor 30 are connected to one side of the movable contactor 40, and inlet-side fixed contacts 31 of the fixed contactor 30 are connected or separated from another side of the movable contactor 40 by a movement of the movable contactor 40.
Operation of the above-mentioned circuit breaker will be described in detail.
First, the movable contactors 40 in a normal condition are connected to the respective inlet-side fixed contacts 31 of the fixed contactors 30. Then, a current is introduced through the inlet-side fixed contacts 31 of the fixed contactors 30, and flows in an inner path of the movable contactors 40. The current flowing in the inner path of the movable contactors 40 flows to a load device through the outlet-side fixed contacts 32 of the fixed contactors 30.
If an overcurrent or a fault current is detected, the operating mechanism 50 operates by an internal operating mechanism. While the movable contactors 40 angularly rotate due to a movement of the operating mechanism 50, the movable contacts of the movable contactors 40 are spaced from the inlet-side fixed contacts of the fixed contactors 30, thereby breaking the current flow.
As an amount of power needed is increased, there is an increasing need for a circuit breaker having a high conducted current. That is, a circuit breaker is required to have a conducted current in the range of 4000 A (ampere) to 6300 A. In order to increase such conducted current, the body frame 10 of the circuit breaker should be enlarged.
The body frame 10 of the circuit breaker is generally manufactured by injection-molding. If the body frame 10 of the circuit breaker becomes larger in size, a large-sized mold for manufacturing the body frame 10 and injection equipment thereof should be manufactured, thereby increasing a unit cost of manufacture.
As one of the methods to solve these problems, there is a method which couples two body frames 10 used for a small size to each other and then enables to have the same functions and roles as one large-sized body frame 10.
As a method for coupling the two small-sized body frames 10, as shown in FIG. 3, a resin may be used to join the two small-sized body frames 10. However, such method needs a process for resin molding as well as takes a lot of time for the resin to be hardened, thereby reducing productivity. In addition, the two small-sized body frames 10 are joined together, thereby making it difficult to separate each component when a problem occurs.